By virtue of the lesser requirements for transmission power, lower hardware complexity and greater robustness, frequency modulated continuous wave (FMCW) radar systems often come into consideration as a compact embodiment as an integrated circuit for the front end of the radar system. Such systems are deployed in large numbers, both in the automotive industry and also in telecommunications.
One form of embodiment concerns the FMCW radar system with a single antenna with timing control. When in operation radar systems with single antennae of known art use a time-wise distribution between transmission and reception modes of operation. An FMCW system of known art ((McGregor et al., Switching system for single antenna operation of an S-band FMCW radar, Proc. Inst. Elect. Eng.—Radar, Sonar Navig., 1994, Vol. 141, No. 4, Pages 241-248) uses a commercially available PIN diode as a switching element, which provides a high level of isolation between the transmitter and receiver. Another FMCW radar module of known art (Saito et al., An FM-CW Radar Module With Frontend Switching Heterodyne Receiver, International Microwave Symposium Digest (MTT-S), 1-5 Jun. 1992, Vol. 2, 1 Jun. 1992, Pages 713-716) is based on a superheterodyne receiver.
The documents (U.S. Pat. No. 6,720,912, U.S. Pat. No. 6,972,711, U.S. Pat. No. 7,714,772) are concerned with a single antenna implementation of the superhet front end based on use of the switching element. A transmission/reception switch on the antenna is used so as to be able to use the single antenna for both transmission and reception modes of operation.
The document U.S. Pat. No. 6,720,912 proposes the use of an additional transmission amplifier stage and reception amplifier stage downstream of the transmission/reception switch and to operate this synchronously. This increases the level of isolation between transmitter and receiver.
The document U.S. Pat. No. 6,972,711 is concerned with the utilisation of an additional switching and control network to switch the intermediate frequency (IF) and also the low-frequency oscillator signals, which are provided on a second mixer.
The document U.S. Pat. No. 7,714,772 discloses an extension of the concept in the document U.S. Pat. No. 6,720,912; this envisages additional amplification control blocks for the amplifier stages.
The document DE 60 305 674 T2 concerns a near-field pulse compression radar system.